1. Field of the Invention
The present invention relates to an air conditioner that comprises a function that prevents the propagation of microorganisms in the evaporator and in the environs thereof or, more particularly, to a vehicle air conditioner and an antibacterial case arranged in the air passageway thereof.
2. Description of the Related Art
The activity of microorganisms such as bacteria that propagate in air conditioners is recognized as a major cause of the generation of unpleasant odours from car air conditioners. Environments such as this in which bacteria propagation is liable to occur are created in air conditioners due to the water that condenses as dew that is generated by the evaporator core. Antibacterial treatments and drying of the units have been considered as measures for preventing microorganism propagation.
Although a significant number of methods involving the compounding of antibacterial agents in the resin of the air conditioner have been attempted, there is a problem inherent to these methods in that the effect of the antibacterial agent is lost when dust accumulates on the antibacterial agent. Accordingly, the use of a volatile antibacterial agent has been proposed as a measure to deal with this (for example Japanese Unexamined Patent Application 11-211126, Japanese Unexamined Patent Application 11-211126 and Japanese Patent 6-78821).
Although the techniques used in the prior art have involved the placing of the volatile antibacterial agent within the air conditioner, these techniques gave no consideration to the fact that, when a volatile antibacterial agent is provided in a vehicle air conditioner, because temperatures within the air conditioner reach temperature of up to 50° C. in the summer months, the level of volatilization of the antibacterial agent increases and the lifespan thereof is shortened.
Thereupon, the focus of research changed to the development of an antibacterial agent case where it became known that, because of the gas-permeable property of polypropylene, if isocyanates and, in particular, ally isothiocyanate (AIT), was employed as the antibacterial agent, the reliance on temperature and the reliance on the quantity of blown air within the air passageway with respect to the level of volatilization could be improved by controlling the thickness of the wall.